Ext.tree.TreeLoader.prototype.doPreload = function(node){
	if(node.text=='yanfa'){
		alert(node.attributes.children.length);
	}
	if(node.attributes.children){
		if(node.childNodes.length < 1){ 
			var cs = node.attributes.children;
			node.beginUpdate();
			for(var i = 0, len = cs.length; i < len; i++){
				if(cs[i] instanceof Ext.tree.TreeNode){
					var cn = node.appendChild(cs[i]);
				}else{
					var cn = node.appendChild(this.createNode(cs[i]));
				}
				if(this.preloadChildren){
					this.doPreload(cn);
				}
			}
			node.endUpdate();
		}
		return true;
	}else {
		return false;
	}
}
Ext.tree.TreeLoader.prototype.createNode=function(attr){
        
	if(this.baseAttrs){
		Ext.applyIf(attr, this.baseAttrs);
	}
	if(this.applyLoader !== false){
		//attr.loader = this;
	}
	if(typeof attr.uiProvider == 'string'){
	   attr.uiProvider = this.uiProviders[attr.uiProvider] || eval(attr.uiProvider);
	}
	return(attr.leaf ?
					new Ext.tree.TreeNode(attr) :
					new Ext.tree.AsyncTreeNode(attr));
}
Ext.tree.TreeNodeUI.prototype.onOver = function(e){
	this.addClass('x-tree-node-over');
	this.node.getOwnerTree().selModel.selNode=this.node;
}